package common

const (
	defaultPageSize = 10
)

type PageRequest struct {
	Page     int `json:"page"`
	PageSize int `json:"page_size"`
}

type PageResponse struct {
	Page       int   `json:"page"`
	PageSize   int   `json:"page_size"`
	TotalCount int64 `json:"total_count"`
}

type Paginator struct {
	Page       int
	PageSize   int
	LimitStart int
}

// 根据分页请求，获取分页结果
func (this PageRequest) GetPaginator() Paginator {
	return getPaginator(this.Page, this.PageSize)
}

func getPaginator(page int, pageSize int) Paginator {
	paginator := Paginator{}
	if pageSize == 0 {
		paginator.PageSize = defaultPageSize
	} else {
		paginator.PageSize = pageSize
	}
	if page == 0 {
		paginator.Page = 1
		paginator.LimitStart = 0
	} else {
		paginator.Page = page
		paginator.LimitStart = (paginator.Page - 1) * paginator.PageSize
	}
	return paginator
}

// 根据分页结果，获取分页响应
func (this Paginator) GetPageResponse(count int64) PageResponse {
	return PageResponse{
		Page:       this.Page,
		PageSize:   this.PageSize,
		TotalCount: count,
	}
}